He might try to prove his innocence by gathering evidence. For example, if his sisters wrongly blame him for breaking something, he could look for proof that he wasn't even near the item when it broke.
One reason could be for the sake of creating drama. Writers might blame Naruto in fanfiction to stir up conflict and make the story more interesting. For example, they could make him the cause of a rift between other characters.
One great 'Percy gets wrongly blamed' fanfiction is 'The False Accusation'. In it, Percy is wrongly blamed for stealing a powerful artifact. The story then unfolds as he tries to clear his name while also dealing with the real culprit who is trying to frame him further.
It could mean that the character Naruto in some context is being held responsible or criticized in fan - made fictional works. Maybe some fanfictions depict Naruto in a way that goes against his original character traits and this has led to a perception of 'blame' within the fanfiction community.
Well, it creates drama. Readers like to see their favorite characters in difficult situations. When Percy is wrongly blamed, it makes us feel for him and root for his vindication.
The 'harry is blamed fanfic' could cover a wide range of scenarios. It might be set in an alternate universe where Harry has different relationships and circumstances. He could be blamed for a change in the magical balance, perhaps due to a prophecy that was misinterpreted. Or it could be a more personal blame, like being blamed for the emotional distress of another character. Fanfics often take the existing characters and put them in new and unexpected situations.
In some Twilight fanfiction, Edward might be blamed because of his over - protective nature. He often makes decisions for Bella without fully considering her own desires, which can be seen as controlling and thus draw blame.
Well, in a lot of fanfiction, the idea is that Tony's creation of Ultron was a complex situation. He was acting out of fear for the safety of the Earth. The Avengers had faced many threats, and he thought an AI like Ultron could be a preemptive defense. So, the fanfiction authors don't blame him as they understand his motivation and the unforeseen consequences that came with his experiment.
Jealousy could be a reason. Maybe Lincoln got something they wanted, like a new game or a special privilege, and they're trying to get him in trouble out of spite.
Perhaps it was a weapon created by a rogue ninja with unique powers. And for some reason, it found its way to Naruto in Wave. It might also be a weapon that was enchanted by a sorcerer long ago and has special abilities that Naruto will discover as he uses it.